Emulsifiable lubricant compositions



United States Patent a 7 2,975,132 7 EMULSIFIABLE LUBRICANT COMPOSITIONS Richard L. Feral, El came, cane, assignor to California Research Corporatihn, San Francisco, Calif., a-corp'oration of Delaware Nonrawi'n "Filed time 18, 1956, see No. 591,793

2 Claims. or. 252-335 invention is directed; to lubricant compositions emulsifiable in water. The lubrieating compositions of invention are particularly. suitable for the lubrication of large low-speed diesel engines.

For the purpose of keeping maintenance costs as low as possible, low-speed diesel engines havevfor many years used high-quality, relatively expensive fuels. In more recent years, attempts have been made to use a lower quality fuel, that is, a heavy fuel oil, particularly, by theoperators of dieselengines of the cross-head type used in; marine service. Suchlower quality fuelsrhave high. sulfur contents, for example, from 1% to 5%, by weight; and the sulfur in these fuels adds to the over-all formation. of carbondeposits and acidic components, causing ncrease in wear. More recently it has been'discovered that high-sulfur fuels can be used in the operation of large, low-speed diesel engines if water-oil emulsion type lubricants are used for upper head cylinder lubrication. It is noticed that the use ofemulsion type lubricants for such service results in a marked improvement in piston and cylinder cleanliness in addition to the considerable reduction in wear relative to that obtained with lubricants previously used in conjunction with high-sulfur fuels, Water-oil. emulsion lubricants of themselves are not new in the art of lubrication. For example, in additionto the above, Water-oil emulsions are used for lubrication in metal working operations and in the lubricationof steam cylinders, A primary reason for the lack Of'acceptance of emulsionlubricants where, such possibly could be used has been the difficulty of inhibiting the formationof rust and'corrosiom Ditficulties have been encountered in the use of wateroil emulsions in lubrication of; marine diesel engines. In cold climates, for example, the aqueous phase of the emulsionsfcan become frozen, resulting in a composition which is not re-emulsifiable. Furthermore, when the marine emulsion lubricants are stored in engine rooms aboard ships, the high temperatures tend to make the emulsions unstable. Also, thepresence of large quantities Of water in the emulsion lubricants makes the/trans? 2,975,132 Patented "M rust-inhibited lubricating oil composition could, be or; tainedin accordancewiththe present invention; I i

The oil-soluble. divalent, metal sulfonates used herein. include alkaline-earth metal sulfonates, wherein the stile fonic. acids from which the. salts are derived have, molecular weights ranging froni400-700. It is preferred, that the molecular v'vei'ghts of the sulfonic acids used in the formation of the sulfonates be from 450 to 550. The, metal sulfonates used herein. include the metal salts of synthetic sulfonie acids and petroleum sulfonic acids; and these may be exemplified by calcium white oil benzene sulfonate, calcium dipolypropene benzene sulfonate, calcinmmahogany petroleum sulfonate, calcium ,triacontyl sulfonate, calcium. didodecylbenzene sulfonate, etc.

Preferably, thernetal sulfonates are somewhat basic; that is,thesulfonatescontain a greater amount of metal than that necessary forfthe'neutralization of the sulfonic acids from. which they are derived. F or example, a metal mahogany petroleumsulfonatemay contain as much as 100 mol percent metal in excess of that essential for, the formation of neutral r'netal mahogany petroleum sulfonate.

. Phenates which are contemplatedfor use herein in combinationfwithitherabovenoted sulfonates include oilsoluble divalent. metal salts of phenol and substituted phenols, and oil-solublesulfurized divalent metal salts, of phenol and substituted phenols Examples of these include the sulfurizedallcaline earth metal phenates, such as, sulfuriz'ed calcium salts of octylphenol, decylphenol, dodecylphenol, pen'ta'dec'ylphenol, hexadecylphenol, octadecylphenol, triacontylphenol, polypropenephenol, etc.

Divalent metal phenates which'areparticularly eife'ctive herein in combination with divalent metal sulfon'ates in the formation of-water-emuls'ifiable lubricating oil com: positions are the basic sulfurized divalent metal phenates, describe'din Walker-Shiells U.S.-Patent 2,680,096. These particular, sulfurized metal phenates have metal contents as great. as, 100% or. more in excess of the metal contents of neutral sulfurized metalphenates. The water-soluble divalent metal salts of organic acids of the en'iulsifiable, lubricating Oil compositions of this invention include thealkaline earth metal salts, such 'ascalcium salts, of organic acids, such as formic acid, acetic, acid, propionicacid, butyric acid, hydroxybutyric acid,- maleic acid, 'salicylic acid, phthalic acid, etc. It is preferred to use, the calcium salts of the aliphatic mono: basicacidscontaining'from 1 to 4 carbon atoms.

- .Suitablelubricating oils which are useful in theformag tion.of,the,water-in=oil emulsions of this invention, in:

' ing, etc.; various crude oils, such as paraffinic, naphthenic;

portation of these lubricants to the point of use '(and v subsequent storage) unnecessarily expensive,

In accordance with this invention, it has been discovered that a remarkably 'elfective water-emulsifiable lubricant useful for upper cylinder lubr'ication in diesel engines is Obtained by the formation of a composition comprising a major proportion of an oil of lubricating viscosity, and minor proportions of an oil-soluble, divalent metal 'sulfonate, an oil-soluble divalent metal phenate, and a water-soluble divalent metal salt of an organic acid. Such a water-emulsifiable lubricant is obtained by substantial removal of the water phase from a water-in-oil emulsion comprising water, an oil of lubricating viscosity, an oil-soluble divalent metal sulfonate, an oil-soluble divalent metal phenate, and a water-soluble metal salt of an organic acid. i

It was entirely unexpected that a readily emulsifi'able,

' Y The preferred amounts'ofthe 'abov'e'components are or mixed basecrude oils, or; suchas thosewhich can, be obtained by. synthesijs, ,e.g., the Fischer-Tropsch .process. Lubricating oil's also include those derived from coal products and synthetic eil's', e.g.',"alkylene polymers, dicarboxylic acid esters,.. and; liquid esters of acids of phos-' phor'us and silicon. The preferred lubricating oils for, this inventionra're thepet'roleum oils of lubricating VlS COS- In the formation of the water-emulsifiable lubricantherein, thev lubricating'oil'is present as a major component of the composition, that is, in an amount of about 60%;. to about 98%, by weight; the water-soluble alkaline earth metal salts are present in amounts of about 0.2% to about l2%; the sulfonates are present in amounts of about, 0.5% to about 5%; and the phenates are present in amounts of about 0.5 to about 5 with the minimum total amount 'of sulfonate'and phenate being 1%, and; the'maximum total amount of sulfona'te and phenate bef ing about 10%.

- 3 as follows: lubricating oil, about 75% to about 90%, by weight; water-soluble organic acid salt, about 4% to about 9%, by weight; sulfonates, about 1.5% to about 2.5%, by weight; and phenates, about 1.5% to about 2.5%, by weight.

Thus, the emulsion lubricating compositions prepared from the above-described emulsifiable lubricating oil compositions may contain from 2% to 60%, by weight, water; 30% to 98%, by weight, of an oil of lubricating viscosity; 0.5% to 4%, by weight, of sulfonate; 0.5% to 4%, by weight, of phenate; and from 0.2% to 10%, by weight, of the water-soluble salts of organic acids.

It is particularly preferred that the total amounts of sulfonates and phenates present in the water-oil emulsion lubricant do not exceed a maximum amount of 6%. Water-oil emulsion lubricants containing total amounts in excess of about 6%, by weight, tend to be unstable.

The mol ratios in which the sulfonates and phenates are present in the emulsifiable lubricant herein are critical; that is, the stability of the water-in-oil emulsions prepared from the emulsifiable lubricants of this invention is dependent on the sulfonate-phenate mol ratio. Although the sulfonate-phenate mol ratios can have values varying from 0.5 to 2.0, it is preferred that the sulfonate-phenate mol ratios have values varying from 0.75 to 1.25.

The water-oil emulsion lubricants from which the emulsifiable lubricants of the present invention are obtaiued contain as much as 60% water, by weight. That is, the water-oil emulsion can contain as much as 60% water and, by substantial removal of the water phase, a composition containing about water is obtained.

j The water may be removed by distillation at atmospheric pressures, by flashing removal through changes of pressures, or by other available means.

T A water-in-oil emulsion lubricant can be obtained by forming an admixture comprising an aqueous solution of an oil-soluble salt of an organic acid (the water content being such as to result in an emulsion containing a maximum of about 60%, by weight, of water); an oil of lubricating viscosity; an oil-soluble divalent metal sulfonate; and an oil-soluble divalent metal phenate at temperatures in the range of about 90 F. to about 200 F., followed by cooling to room temperature. (When water-oil emulsions are prepared with the lower concentrations of the watersoluble salts of organic acids, the temperature of preparation may be as low as room temperature.) From this water-oil emulsion can be prepared a substantially water-free composition which is reemulsifiable. The water-oil emulsion is heated to a temperature at which the water vaporizes (for example, distillation) for a time sufficient to remove substantially all of the water phase. It is preferred to heat to a temperature less than 230 F. at atmospheric pressure (or temperatures equivalent thereto at increased or reduced pressures).

The following examples illustrate the preparation of the lubricating compositions of this invention.

EXAMPLE 1 8 grams of a 40% lubricating oil solution of a basic sulfurized calcium alkyl phenate (the concentrate containing 2.9% sulfur and 4.5% calcium, and the alkyl group being derived from a tetrapropylene polymer and containing an average of 12 to 14 carbon atoms), and 8 grams of a 40% lubricating oil solution of a slightly basic calcium petroleum sulfonate having a molecular weight of about 1040 (the concentrate containing 2.35% calcium) was blended into 276 grams of a California naphthenic base 60 VI SAE 30 oil. To this oil composition was slowly added 108 grams of 26% aqueous solution of calcium acetate monohydrate, keeping the temperature between 140 F. to 160 F. The resulting emulsion was passed through a Manton-Gaulin homogenizer at 4000 psi. The efiluent emulsion was rapidly cooled to 95 F.

The resulting composition contained 1.76% calcium, 0.47% sulfur; had a neutralization number (mgs. KOH per gram sample) of 46.4, and a sulfated residue (by the ASTM D-874 method) of 5.92%.

EXAMPLE 2 The water-in-oil emulsion of Example 1, above, was heated on a steam plate until substantially all of the water phase had been removed by distillation, then cooled to room temperature. The resulting emulsifiable lubricant contained 2.17% calcium.

In the dehydration step of forming the emulsifiable lubricating oil compositions, it is preferred that the temperatures do not exceed (are less than) 230 F. at atmospheric pressures.

grams of water was then added to the above oil composition, and by simple stirring means the water-inoil emulsion lubricant of Example 1 was again formed. Although, for reasons of conserving time, it is preferred to use mechanical mixing means to re-emulsify the water, an emulsion can be obtained by vigorous hand stirring.

EXAMPLE 3 A stable water-oil emulsion lubricant containing 60% water was prepared by vigorously stirring at temperatures between F. and F. a mixture consisting of 2 grams of a 40% oil concentrate of basic sulfurized calcium alkyl phenate (the alkyl group derived from a polypropylene polymer having an average of 12 to 14 carbon atoms, and the concentrate containing 4.5% calcium, by weight, and 2.9% sulfur); 2 grams of a 40% oil concen trate of a slightly basic calcium petroleum sulfonate having a molecular weight of about 1040 (the concentrate containing 2.35 by weight, calcium); 7 grams of calcium acetate monohydrate; 60 grams of water; and 29 grams of a California naphthenic SAE 30 base oil.

Table I hereinbelow presents data showing the criticality of the sulfonate-phenate mol ratios in forming stable water-oil emulsions from the emulsifiable lubricating oil compositions of this invention.

The water-in-oil emulsions used in obtaining the data of Table I were prepared according to the process described in Example I. The emulsions were then allowed to stand in open vessels at the designated temperature for the noted period of time. The relative stability of the emulsions was shown by the amount of skin which formed on the surface of the emulsions. The greater the amount of skin, the less stable was the emulsion. This skin was similar to that formed in an open can of paint which has been standing as such for a period of time.

Table I Bulfonate- Skin alter Experiment No. Phenate 72 hours at M01 Ratio 110 F.

1 0.8 Trace. 1. 6 Trace. 3 0.8 Trace.

1. 2 Medium 0. 5 Medium 0.8 Trace. 0. 8 Heavy 3. 2 Heavy The emulsion lubricant of Example 1 hereinabove was tested in a Lauson gasoline engine. The test was carried out as follows: A single cylinder Lauson gasoline sparkignition engine, 2% inch bore and 2% inch stroke, loaded with a three-phase induction generator, was operated under extremely severe conditions designed to develop fully the tendency of the lubricant to deteriorate with gum formation and piston ring sticking. The engine was operated at 1200 r.p.m., the engine jacket temperature was maintained at 375 F., the emulsion lubricant was maintained at 225 F., and the engine was inspected after a 30-hour period of operation. After this operation, the piston skirt was clean, with negligible gum deposits.

For determination of the anti-rusting characteristics of the compositions, steel cans were sandblasted, and lubricating emulsions described hereinabove were placed therein for a period of two weeks at 110 F. No rust was noted after this period.

It is particularly remarkable that the phenate-sulfonate water-in-oil emulsion compositions of this invention leave no residual deposit after evaporation of the water phase. The calcium acetate appears to be peptized in the oilsulfonate-phenate composition. When treated in exactly the same manner as described in Example 2 hereinabove, a commercially available emulsion lubricant left large granular deposits of calcium acetate, and, after numerous attempts, the composition remaining could not be reemulsified.

I claim:

1. A stable water-in-oil emulsion lubricant consisting essentially of from about 30% to 98%, by weight, of a petroleum lubricating oil, from 2% to 60%, by weight, of water, from 4% to 8%, by weight, of a water-soluble calcium salt of an aliphatic monobasic acid containing from 1 to 4 carbon atoms, from 1.5% to 2.5% of an oil-soluble calcium petroleum sulfonate, and from 1.5% to 2.5 of an oil-soluble sulfurized calcium alkyl phenate, wherein the alkyl radical is derived from propylene polymers having an average of about 12 carbon atoms, and wherein the sulfonate-phenate mol ratio has a value from 0.75 to 1.25.

2. A stable water-in-oil emulsion lubricant consisting essentially of from about 30% to 98%, by weight, of a petroleum lubricating oil, from 2% to by weight, of water, from 4% to 8%, by weight, of calcium acetate,

from 1.5% to 2.5 of an oil-soluble calcium petroleum sulfonate, and from 1.5 to 2.5% of an oil-soluble sulfurized calcium alkyl phenate, wherein the alkyl radical is derived from propylene polymers containing about 12 carbon atoms, wherein the sulfonate-phenate mol ratio has a value from 0.75 to 1.25.

References Cited in the file of this patent UNITED STATES PATENTS 2,079,051 Sullivan et al. May 4, 1937 2,362,289 Mikeska Nov. 7, 1944 2,367,470 Neely et al. Jan. 16, 1945 2,372,411 Van Ess et al Mar. 27, 1945 2,406,564 Rogers et a1 Aug. 27, 1946 2,472,517 Cantrell et al. June 7, 1949 2,472,552 Smith et al. June 7, 1949 2,480,664 McNab et al. Aug. 30, 1949 2,491,649 Duncan et al. Dec. 20, 1949 2,518,379 Rogers et a1. Aug. 8, 1950 2,671,758 Vinograd et al. Mar. 9, 1954 2,680,096 Walker et al. June 1, 1954 2,744,083 Moody et al. May 1, 1956 2,744,870 Stillebroer et al. May 8, 1956 2,761,845 Rogers et a1. Sept. 4, 1956 2,766,291 Weissberg et al. Oct. 9, 1956 2,820,007 Van Der Minne et al. Jan. 14, 1958 FOREIGN PATENTS 704,425 Great Britain Ian. 13, 1954 

1. A STABLE WATER-IN-OIL EMULSION LUBRICANT CONSISTING ESSENTIALLY OF FROM ABOUT 30% TO 98%, BY WEIGHT, OF A PETROLEUM LUBRICATING OIL, FROM 2% TO 60%, BY WEIGHT, OF WATER, FROM 4% TO 8%, BY WEIGHT, OF A WATER-SOLUBLE CALCIUM SALT OF AN ALIPHATIC MONOBASIC ACID CONTAINING FROM 1 TO 4 CARBON ATOMS, FROM 1.5% TO 2.5% OF AN OIL-SOLUBLE CALCIUM PETROLEUM SULFONATE, AND FROM 1.5% TO 2.5% OF AN OIL-SOLUBLE SULFURIZED CALCIUM ALKYL PHENATE, WHEREIN THE ALKYL RADICAL IS DERIVED FROM PROPYLENE POLYMERS HAVING AN AVERAGE OF ABOUT 12 CARBON ATOMS, AND WHEREIN THE SULFONATE-PHENATE MOL RATIO HAS A VALUE FROM 0.75 TO 1.25. 